Human Circulatory System

Question 1

A. structures

Answer 1

1. blood
2. vessels
3. heart (pump)
4. accessory organs cleanse blood

Question 2

A. structures
1. blood

Answer 2

made up of plasma and cells

a) plasma - water plus molecules (carbon dioxide, proteins, nutrients, wastes, hormones, salts, ions)
b) cells
i. red blood cells (erythrocytes)
carry oxygen
- do not have nucleus
ii. white blood cells (leukocytes)
immune system cells
- make pus
- fight for invading pathogens and
show to other immune system
iii. platelets blood clotting
- much smaller than red blood cells
- release a protein called fibrin

Question 3

A. structures
2. vessels

Answer 3

a) arteries (and arterioles)
i. carry blood away from heart
ii. elastic, muscular, thick walled
- muscular could contract
- thick walled because they are under
pressure
b) capillaries
i. transfer of carried materials
ii. thin walled for diffusion
- made of simple squamous
epithelium tissue
c) veins (and venules)
i. return blood to the heart
- after leaving capillaries
ii. have valves
- venule - smallest part of vein
- valves in veins keep blood flowing
towards heart

ex. when you don’t move and not contracting muscles, legs will fall asleep because blood will pool and not move and not forcing blood out of veins

Question 4

A. structures
3. heart (pump)

Answer 4

a) muscular
- two pumps (left and right ventricle)
- left side of the heart works harder
b) 4 chambers separate oxygenated and deoxygenated blood
- right atrium, right ventricle, left
atrium, left ventricle
- interatrial septum, atrioventricular
septum, interventricular septum -
prevents mixing of blood
- mixing of oxidizing and deoxidizig
blood can kill you (usually newborns
known as “blue babies”
c) 4 valves prevent backflow of blood
- blood always moves the right direction because of valves
i. atrioventricular valve structure
- cusps
- chordae tendinae
- papillary muscle
a. right atrioventricular valve
(tricuspid valve)
b. left atrioventricular valve
(mitral/bicuspid vale)
ii. semilunar valves
a. pulmonary semilunar valve
b. aortic semilunar valve
d) has its own blood supply
- from coronary arteries
- blood carries oxygen and glucose

• bypass or angeoplasy could fix
  blockages
• blockages: oxygen demand is higher
  e) has own peacemaker to coordinate heartbeat
• don’t need to pump often when
  sleeping because oxygen is not
  needed as much than when you are
  awake and active
• the brain tells the heart to pump
  based of carbon dioxide and oxygen
• sinoatrial node fires - collection of
  nerves that sends signals out
• atria contract gives signal to
  atrioventricular node fires that gives
  more signals then ventricles contract
  ^ this happens again and again and
  again

Question 5

A. structures
4. accessory organs cleanse blood

Answer 5

a) liver - removes toxins
b) kidneys - removes wastes
c) spleen - removes debris and old cells and filters blood too

Question 6

B. process of circulation

Answer 6

systemic circuit and pulmonary circuit (separated by septum)

1. in the heart…
2. in the body…

Question 7

B. process of circulation
1. in the heart…

Answer 7

a) atria contract… fill ventricles
b) ventricles contract… force blood out of heart, into arteries
c) atria refill as ventricles empty
cycle continues…

Question 8

B. process of circulation
2. in the body…

Answer 8

a) deoxygenated blood returns to heart from body (-O2)
- blood enters atrium
- ventricles contract forcing
deoxygenated blood towards lungs
- blood acquires oxygen in lungs
- oxygenated blood returns to heart
- atrium contracts forcing oxygenated
blood into ventricle
- ventricle contracts forcing
oxygenated blood out toward body
- blood exchanges oxygen with tissues before returning to heart